Deacon The Deacon was an advanced solid rocket motor design cancelled at the end of World War II. In 1947 NACA began using reworked surplus motors to boost instrumented subscale aircraft models to speeds of up to Mach 4. They became a workhorse for the Agency's aerodynamic research, resulting in new production. Thousands were flown, until, by the end of the 1950's, supersonic wind tunnels took over the job. More...